Make sure the rubber channel is aligned to both holes. Hold the pad assembly up to the light to confirm. It should look like when you look into a blond's ear, you should see light coming through from the other side. Just a joke!!! Don't flame me... Sometimes a part of the brake material will extend into the "passage way" for the pin, or the pad isn't pushed all the way in. Also, excess rubber compound might be in the way as a result of the moulding process. It's always a good idea to check this out before inserting the pad. If necessary, take a knife and clean it up so the pin can easily slide through.